Thermostatic devices



June 6, 1961 J. E. SHERLOCK 2,987,257

THERMOSTATIC DEVICES Filed Sept. 5, 1958 2 Sheets-Sheet 1 Inventor JOHNE. SHERLOCK I By Hitima.

A ttorneyS June 6, 1961 SHERLOCK 2,987,257

THERMOSTATIC DEVICES Filed Sept. 5, 1958 2 Shets-Sheet 2 Inventor Tot-wsownao sHEkLoc By Hmq- 6811mm- A ttorn e y United States Patent2,987,257 THERMOSTATIC DEVICES John E. Sherlock, Shepperton, England,assignor to The British Thermostat Company Limited, Sunbury-on- Thames,England Filed Sept. 3, 1958, Ser. No. 758,826 Claims priority,application Great Britain Sept. 3, 1957 11 Claims. (Cl. 236-99) Thisinvention relates to thermostatically controlled gas valves forapplication to cooking ovens and the like and is an improvement in ormodification of the gas valve assembly described and claimed in Britishpatent specification No. 773,593.

In the aforesaid specification there is claimed a gas valve assembly forthe purpose mentioned provided with latching means to lock a rotary plugvalve member or cock in its closed and fully open positions and a commonhand-operated member for turning the cock between said positions butcapable of disengagement in the fully open position from the latchingmeans for independent operation to vary the temperature at which athermostatically controlled valve will reduce or cut off the gas supplyto the burners; and the particular latching means therein disclosedcomprises a forked arm fast with the cock and engaged by a crank pinfixed to the hand-operated member whose axis is parallel to and spacedfrom the axis of said cock, and a non-rotatable, spring-loaded lockplate having projections or abutments which co-operate with the forkedarm to retain the cock in each of its two limit positions, movement ofthe handoperated member beyond the fully open position of the cock beingpermitted by the disengagement of the crank pin from the forked armwhilst freeing of the cock for movement to the other limit position iseffected by displacement of the lock plate against its spring.

The object of the present invention is to provide an improved andsimplified form of latching means which facilitates manufacture andassembly.

According to the invention the latching means comprises a forked armwhich is so shaped that its movement in both directions is limited byabutment with the hand-operated member.

An embodiment of the invention will now be described with reference tothe accompanying drawings of which:

FIG. 1 is a sectional elevation of the gas valve,

FIG. 2 is a plan view,

FIGURE 2A is a plan view similar to FIGURE 2 but showing the valve inclosed position, and

P16. 3 is an end elevation looking from the left of FIG. 1.

Referring to FIG. 1 of the drawings, a gas supply cock 1 of the rotaryplug type is mounted in a casing 2 having an inlet passage 3 adapted tobe connected to a main gas supply and an outlet passage 4 adapted to beconnected to the gas burners in an oven. Communication between the inletand outlet passages is controlled by a valve member 5 movable toward oraway from a normally fixed but adjustable seating 6 by the operation ofa flexible metallic bellows device 7 connected in known manner by acapillary tube 8 to a thermally sensitive phial (not shown) disposedwithin or near the oven. The bellows, tube and phial form a closedsystem charged with a substance whose expansion under heat causes thebellows 7 to expand and move the valve member 5 towards its seating 6.

The bellows 7 is loaded by a spring 9 and acts on the valve member 5 viaan ambient temperature compensating bi-metallic disc 10 and an overloadspring 11 both of which register with a push rod 12. The latter isguided at its upper end in a sleeve 13 integral with ice the valve seat6. The spring 11 is adapted to yield by splaying its extremities outbeyond the periphery of the valve member 5 if the bellows continues toexpand after the valve is closed.

A by-pass passage 14 in an adjustable member 15 permits a little gas toescape after the valve 5 has been seated in order to prevent the burnerflames from being extinguished when the valve is closed.

In order to adjust the position of the seating 6 to vary the temperaturerange of the instrument, there is provided a push rod 16 carried in asleeve 17 threaded into what is virtually an upward extension 18 of thecasing 2. The sleeve 17 may be rotated by a hand-operated member in theform of a hollow spindle 19 slotted at 20 to engage with a control knobnot shown. Such rotation causes the push rod to be moved axially byvirtue of the screw action. A bellows plate 21 rests upon the sleeve 13and is caused to follow the movement of the push rod 16 by a spring 22so as to vary the position of the seat 6 in accordance with the positionof the knob on the spindle 19. A bellows 23 provides a seal between thefixed and movable parts. The initial position of the rod 16 relative tothe sleeve 17 can be varied by means of a trimming screw 24 which isafterwards locked in position by a grub screw 25 acting on a lead pellet26.

The rotation of the cock 1 into the on and 055 position is performed bythe knob on the hollow spindle 19, that is to say the'same knob as thatwhich adjusts the position of the valve seat 6. For this purpose, thespindle 19 is provided with a latch plate 27 carrying a pin 28 slidingin a slot 29 in a forked arm 30 fixed to the spindle 31 of the cock 1.The forked arm 3i) has a Geneva cross configuration, the two fingersdefining the slot 29 having arcuate outer edges 32 and 33 of the sameradius as the enlarged portion 34 of the spindle 19.

When the cock 1 is in the closed position, the innermost curved edge 32bears closely against the periphery of the portion 34 so that the forkedarm 30 and the cock are held against movement. Further clockwise (asseen in FIG. 2) movement of the spindle 19 (which would disengage thepin 28 from the slot 29) is prevented in this position by the upper (inFIG. 2) edge of the latch plate 27 coming into contact with the leftband edge of a latch 35. Anticlockwise movement of the spindle 19 isprevented by the left hand edge of a projection 36 coming up against theright hand side of the latch 35.

Before the spindle 19 can be turned to open the cock 1, it has to bepushed in (that is to say, downwards in FIGS. 1 and 3) against a spring37. Such movement of the portion 34 unlocks the forked arm 30 while thecorresponding movement of the projection 36 brings it into the plane ofa clearance slot 38 in the latch 35. This slot is sufficiently deepradially to allow the passage of the projection 36 but not of the latchplate 27. Consequently, anticlockwise rotation of the spindle 19 (asseen in FIG. 2) is now possible, clockwise rotation is still prevented.

As the spindle 19 is rotated, it opens the cock 1, a slot 39 in thespindle 19 permitting the extremity of the forked arm 30 to pass throughthe mid position shown in the drawings. Once the projection 36 hasentered the slot 38 the spindle 19 is prevented from axial movementunder the influence of spring 37 until the cock 1 has been fully openedand the pin 28 is at the end of the slot 29 in the forked arm 30. Atthis point the projection 36 leaves the latch 35 and the spindle 19moves outwards (upwards in FIG. 1). This traps the edge 33 of the forkedarm 30 against the portion 34 so locking the cock in the open position.

The spindle 19 can now be rotated further in an anticlockwise direction(FIG. 2) to vary the position of the seating 6 in the manner alreadydescribed. This causes the pin 28 to leave the slot 29. It will beappreciated that in order to lock the cock 1 in the open position it isdesirable to prevent further inward movement of the spindle 19. This isachieved by a stop 40 which engages first on the underside of the latchplate 27 and then on the underside of the projection 36. The gap betweenthese two is less than the width of the stop 40. Extreme anticlockwisemovement of the spindle 19 is limited by the lower (as seen in FIG. 2)edge of the latch plate 27 coming into contact with the right hand sideof the latch 35. In this position the projection 36 is still in contactwith the stop 40 so that the cock 1 cannot be unlocked.

I claim: I

1. In a gas supply valve having a passage, a rotary valve plug in thepassage adapted to be turned between fully open and fully closedpositions, a manually rotatable member mounted for axial displacement,means for latching said member against rotatable movement and forlocking said plug against rotation when the plug is in fully closedposition, means for axially displacing said member to unlatch saidmember for rotation and at the same time to unlock said plug forrotation, rotation of said member in one direction being efiective toturn said plug to fully open position, a thermostatically-controlledvalve in said passage having an adjustable part to selectively vary thetemperature range during which said thermostatically controlled valveacts to vary gas flow through the passage, and means providing a motiontransmitting connection between said member and said part for adjustingsaid part when said plug is in said fully open position.

2. In the valve defined in claim 1, means for retaining said member inaxially displaced position during rotation of said valve plug.

3. In the valve defined in claim 1, means effective when said member isdisplaced to plug rotating position for blocking rotation of said memberin the other direction.

4. In the valve defined in claim 1, resilient means effective when saidvalve plug has been rotated to fully open position for axially movingsaid member to the original position it assumed when the valve plug wasfully closed and locking the plug against rotation.

5. In the valve defined in claim 1, an eccentric pin on said memberslidably engaged with a slotted arm on said plug, and at least onearcuate locking face on said arm coacting with a corresponding lockingface on said member.

6. In the valve defined in claim 1, means preventing 4 axialdisplacement of said member during said adjustment of said part.

7. A gas supply valve for controlling the supply of gas to a burner,comprising a rotary plug valve member having a forked operating arm forturning it into closed and fully open positions, said forked arm havingarcuate outer edges, a manually rotatable member having a crank pinmounted eccentrically thereon and engageable with said forked arm toturn said plug valve member between its said positions and disengageablefrom said forked arm by rota-tion of said manually rotatable memberwhile said plug valve member is in its fully open position, meansmounting said manually operable member for axial reciprocable movement,a thermostatically-controlled valve member operable to reduce or cut oifthe supply of gas to the burner, means for operably connecting saidvalve member and said manually rotatable member to adjust saidthermostatically-controlled valve member for operation through a rangeof temperatures, and a spring acting on the manually rotatable member tohold it in a position to lock said forked arm against movement byengagement of one or other of said arcuate outer edges with a similarlycurved portion of the manually rotatable member, said forked arm beingreleasable for plug turning movement only after predetermined axialmovement of said manually rotatable member from said position againstsaid spring.

8. A gas supply valve as claimed in claim 7 in which the forked arm isof Geneva cross configuration and has two fingers defining a crank pinreceiving slot having arcuate outer edges of the same radius as thecurved portion of said manually rotatable member against which they abutin the open or closed positions of the plug valve.

9. A gas supply valve as claimed in claim 7 in which latch means isprovided for limiting movement of said manually operable member.

10. A gas supply valve as claimed in claim 7 in which stop means isprovided to prevent axial displacement of said manually rotatable memberduring adjustment of said thermostatically-controlled valve member.

11. A gas supply valve as claimed in claim 7 in which thethermostatically-controlled gas member valve is acted on by a bellowsassembly through an overload spring in the form of a spider having legswhich are adapted to splay out and slide on the valve member if thebellows continues to expand after said thermostatically-controlled valveis closed.

Matthews Nov. 16, 1937 Fouron Dec. 7, 1954

